This is a multi-essay dissertation in the area of dynamic models of the insurance markets. I study issues in insurance markets by examining individual behavior and industry performance in dynamic settings. My first essay studies household life insurance demand and saving decisions by applying a heterogeneous-agent life cycle model with wage shocks and mortality shocks. This essay proposes the most important determinants of household life insurance demand, and shows the joint decision of life insurance purchase between couples. My second essay focuses on the property-liability insurance market, and aims to study the impact of one catastrophe event on an insurer’s underwritings and capital raising strategy. The two-period cash flow model is built to also explore what kind of insurers can benefit from catastrophic risk underwritings. My third essay extends the second essay by incorporating a dynamic cash flow model with a series of loss shocks. I find the dynamic interaction between the insurer’s balance sheet and its capital rationing resulting from loss shocks. The model generates a non-cyclical behavior of output changes in the insurance market, and this suggests the current asymmetric, unpredictable and random underwriting cycles are temporary responses to loss shocks.

Background: In Vietnam, problems of high out-of-pocket payments for health, leading to catastrophic health expenditure and resulting impoverishment for vulnerable groups, has been at focus in the past decades. Since the beginning of the 1990’s, the Vietnamese government has launched a series of social health insurance reforms to increase prepayment in the health sector and thereby better protect the population from the financial consequences of health problems. Objective: The objective of this thesis is to contribute to the discussion in Vietnam on how large the problems of catastrophic health expenditure are in the population as a whole and in a special subgroup; the elderly households, and to assess important aspects on health insurance as a means to reduce the problems. Methods: Catastrophic health expenditure has been estimated, using an established and common method, from two different data sources; the Epidemiological Field Laboratory for Health Systems Research (FilaBavi) in the Bavi district, and Vietnam Household Living Standards Survey (VHLSS) 2010. Results from two cross-sectional analyses and a panel study have been compared, to gain information on whether the estimates of catastrophic health spending may be overestimated when using cross-sectional data. Then, the size of the problem for one group, the elderly households; hypothesized to be particularly vulnerable in this context, has been estimated. The question of to what extent a health insurance reform; the Health Care Funds for the Poor (HCFP), has offered protection for the insured against health spending is being assessed in another study over the period 2001 – 2007, using propensity score matching. The value that households attach to health insurance has also been explored through a willingness to pay (WTP) study. Results: Comparing results from two cross-sectional studies with a panel study over a full year in which the respondents were interviewed once every month, the estimates of catastrophic spending vary largely. The monthly estimates in the panels study are half as large as the cross-sectional estimates; the latter also having a recall period of one month. Among the elderly households, catastrophic health spending and impoverishment are found to be problems three times as large as for the whole population. However, household health care expenditure as a percentage of total household expenditure was affected by the HCFP, and significantly reduced for the insured. In the study of household WTP for health insurance, it was iiifound that households attach a low value to this insurance form; WTP being only half of household health expenditure. Conclusions: Cross-sectional studies of catastrophic spending with a monthly recall period are likely to be affected by recall bias leading to overestimations through respondents including expenditure in the period preceding the recall period. However, such problems should not deter researchers form studying this phenomenon. If using the same method, estimates of catastrophic spending and impoverishment can be compared between different groups – as for the elderly households – and over time; e.g. studying the protective capacity of health insurance. It should be used more, not less. The VHLSS rounds offer the Vietnamese a possibility to regularly study this. The HCFP were found to be partly protective but important problems remain to be solved, e.g. the fact that people are reluctant to use their health insurance because of e.g. quality problems and possible discrimination of the insured. The findings of a low WTP for health insurance may be another reflection of this.

Managing public forestland is a challenging enterprise as the government must steward the actions of private forest companies while simultaneously considering public values, natural disturbance, markets, revenue generation and environmental services. Governments use timber sales, volume-based, and area-based tenures to delegate forest harvesting activities to individual timber companies. By delegating forest management, government must wisely navigate the principal-agent relationship to avoid unexpected outcomes. However, the agents’ response is often overlooked despite the likelihood that the agents may possess company-centric financial motivations. The British Columbia context, where the government is facing the aftermath of a catastrophic mountain pine beetle epidemic, provides a fruitful location for the study of the principal-agent dilemma. If forest companies share a future forest focus with the government, such that agents respond with actions that lead to the government’s first best outcome, the government could reduce policy analysis to an examination of the tradeoff between short-term revenue generation and sustainable differentiated product supply. But review of the silviculture funding mechanism reveals that the very regulatory mechanism used to achieve government’s results may affect the future forest estate by reducing the amount of salvage once the value of the forest is degraded below the cost to harvest and regenerate it. Relying primarily on harvest-based silviculture funding, the principal is shown to forego a 20 per cent increase in forest growth in the study area by not using the agents’ forestry expertise to improve the long term productive potential of the forest. A bi-level linear programming model is developed to merge the goals of government with the behavioural responses of the two predominant volume-based tenures used in BC. Results show that the government’s choice of harvest level, timber price and tenure instrument in recognition of agent response is the only way to achieve the government’s forest stewardship objective. Treating each element in isolation neglects the nature of the institutional system and will result not only in unintended outcomes, but very likely, policy failure. / Graduate

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 38-41).

Made available in DSpace on 2014-06-11T19:26:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-06-02Bitstream added on 2014-06-13T19:54:22Z : No. of bitstreams: 1 pellegrina_gj_me_bauru.pdf: 2660732 bytes, checksum: 0864cbe76a5ee930256a1d9b1dc513e7 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A proposta dessa pesquisa foi apresentar um procedimento metodológico para aplicação de um banco de dados de eventos severos em estudos de problemas geoambientais. Sua eficácia foi avaliada considerando ocorrências de movimentos de massa significativos em 15 municípios paulistas, cobrindo o período de setembro de 2009 a fevereiro de 2010. As características geológicas, geomorfológicas, hidrológicas e de ocupação foram consideradas e confrontadas com as situações de tempo atmosférico que contribuíram para a deflagração dos eventos calamitosos. observou-se que o domínio da Zona de Convergência do Atlântico Sul está associado às ocorrências mais catastróficas, especialmente em locais de relevo de morros, saprólitos ou contatos solo-rocha, no Complexo Cristalino também relacionado à ocupação desordenada. O estudo também aplicou os índices de risco e vulnerabilidade proposto por Marcelino et al. (2006), que apontou maior risco nos municípios com reincidências de escorregamentos e maior vulnerabilidade em locais com alta densidade demográfica, elevado índice de pobreza e grande número de idosos. Dessa maneira, a aplicação do banco de dados de eventos severos para problemas de geotecnia ambiental, mostrou-se uma importante ferramenta na determinação de áreas de risco, podendo assim, servir de suporte logístico para órgãos que trabalham com a assistência aos vitimados / The research aimed to present a methodology for implementing a database of severe weather events for geo-environmental evaluations. Its efficiency was assessed by considering significant mass movements occurrences in 15 municipalities of São Paulo state between September 2009 and February 2010. The geological, geomorphological, hydrological, as well as the occupation characteristics of selected areas were compared with the previling weather that contributed to the outbreak of calimitous events. Most of the episodes accurred in hills, saprolits or soil-rock contacts in the Crystalline Complex. The unplanned occupational pattern was also an important contributor to the calamitous occurences. The risk and vulnerability index proposed by Marcelino et al. (2006) was applied and lead to high risk in the municipalities with repeated landslides. The vulnerability was greater in area with high population density, poverty rates end number of elderly people. The study enhanced the importance of a database of calamitous events to evaluate geotechnical problems and proved to be an important tool for determining risk areas. Thus, it may serve as logistical support for agencies that work with the assistance to victims

This thesis examines the problem of impact of catastrophic natural events on insurance and reinsurance markets, with special focus on 2005 hurricane Katrina. It aims to analyze and evaluate the consequences of large scale economic loss on global insurance market. First part of the thesis describes the event and its implications. Impact on oil and gas industry and others is discussed. Main section is focused on repercussions of this event for both local and global insurance markets. Influence on selected subjects and new trends observable after Katrina are considered. Changes to alternative risk transfer instruments after 2005 are investigated.

The presence of cracks in rotors is one of the most dangerous defects of rotating machinery. This can lead to catastrophic failure of the shaft and long out-of-service periods. The occurrence of a crack in a rotating shaft introduces changes in flexibilities which alters the dynamics during operation. This research deals with detecting damage in rotors by means of constantly monitoring the variation in the rotor’s dynamics during normal operating conditions. This project entails a computer finite element section as well as an experimental investigation. The flexibility in the region of the crack is different from an uncracked section. A finite element model of a shaft is built and investigated. The damaged model is the same except that the nodes in the location of the crack are not equivalenced in order to represent the crack. A simple constant cross-sectional shaft with semi-circular transverse surface cracks varying in size have been modelled on the Patran finite element software and a normal modes analysis was done using the Nastran solver. The results revealed a change in the natural frequencies due to the variation in the size of the crack. The experimental investigation involved creating sample shafts with damage positioned in them that would closely resemble what one may find in actual real-life situations and the dynamics during rotation with various torsional loadings are investigated and monitored using three methods. A fibre-optical sensor, Digital image correlation system and telemetry strain gauges were used. Undersampling techniques were used for the DIC system. Results showed that the fibre-optic sensor is by far the most favourable as it is able to detect damage under constant operation. The finite element model was updated by re-modelling the geometry, damage and material properties. The solution of the analysis matched the experimental results closely and model verification was achieved. / Dissertation (MEng)--University of Pretoria, 2013. / Mechanical and Aeronautical Engineering / unrestricted

Cross-domain intrusion detection, a critical component of cybersecurity, involves evaluating the performance of neural networks across diverse datasets or databases. The ability of intrusion detection systems to effectively adapt to new threats and data sources is paramount for safeguarding networks and sensitive information. This research delves into the intricate world of cross-domain intrusion detection, where neural networks must demonstrate their versatility and adaptability. The results of our experiments expose a significant challenge: the phenomenon known as catastrophic forgetting. This is the tendency of neural networks to forget previously acquired knowledge when exposed to new information. In the context of intrusion detection, it means that as models are sequentially trained on different intrusion detection datasets, their performance on earlier datasets degrades drastically. This degradation poses a substantial threat to the reliability of intrusion detection systems. In response to this challenge, this research investigates potential solutions to mitigate the effects of catastrophic forgetting. We propose the application of continual learning techniques as a means to address this problem. Specifically, we explore the Elastic Weight Consolidation (EWC) algorithm as an example of preserving previously learned knowledge while allowing the model to adapt to new intrusion detection tasks. By examining the performance of neural networks on various intrusion detection datasets, we aim to shed light on the practical implications of catastrophic forgetting and the potential benefits of adopting EWC as a memory-preserving technique. This research underscores the importance of addressing catastrophic forgetting in cross-domain intrusion detection systems. It provides a stepping stone for future endeavours in enhancing multi-task learning and adaptability within the critical domain of intrusion detection, ultimately contributing to the ongoing efforts to fortify cybersecurity defences.

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This article is a literature review about global catastrophic risks. Its contribution is to give an overview of the research field in general and highlight the main potential catastrophic areas linked with recent studies. In many movies and TV shows, we can see our civilization collapse in various ways: Gigantic asteroids hit the earth and obliterate all life, nuclear wars emerge, artificial intelligence evolves and starts wars with humans, pandemics spread, and other kinds of catastrophic events with mass death or extinction of all life happen. Thus, even if these are extreme events and fiction, we should raise the question how likely it is that one or more of these events can occur in the near and far future. Although calculated probabilities of impact are low for the future such as tomorrow, in 10, 100 or a million years from now, this could actually be reality. Nevertheless, why should we care about the risks of these global catastrophic events today and what could be done to prevent or reduce the risk of a global catastrophe? In this paper we will discuss core content, such as different risks and ways to reduce them internationally, as well as the scientific context of the field. In fact, there are events that can be catastrophic on a global scale and happen in the near future, even if we do not know exactly when. Hence, specific risk assessment and proper mitigation strategies are necessary in order to maintain the human population. This article states that serious research is a basis for decision makers in particular, who invest funds in countermeasures.